Polymers of acrylonitrile and nu-substituted amides



Patented Aug. 31, 1954 POLYMERS OF ACRYLONITRILE AND N-SUBSTITUTEDAMIDES David W. Chaney, Nether Providence Township,

Delaware County, Pa., assignor to The Chemstrand Corporation, Decatur,Ala., a corporation of Delaware No Drawing. Original application June 6,1950,

Serial No. 166,550. Divided and this application February 25, 1952,'Serial No. 273,355

2 Claims.

This invention relates to a new class of polymeric materials,compositions, and shaped articles comprising the polymers, and tomethods for producing them. This application is a division of mycopending application, Serial No. 166,550, filed June 6, 1950, nowabandoned.

The new polymeric materials are copolymers of acrylonitrile with amides,a nitrogen atom of Which is directly attached to a radical containingthe C=C linkage.

The amides which are copolymerized with acrylonitrile to produce thecopolymers of this invention have the general formula in which R ishydrogen or an alkyl radical containing from 1 to carbon atoms, or anaryl or aralkyl radical having from 6 to 9 carbons, e. g., phenyl,benzyl, ethylphenyl, etc., R1 is allyl or vinyl, and R2 and R3 arehydrogen, alkyl radicals containing from 1 to 5 carbon atoms, or aryl oraralkyl radicals having from 6 to 9 carbons, and may be the same ordifierent.

Specific examples of the amides which are copolymerized withacrylonitrile in accordance with the invention are allyl urea,N-vinyl-N-methyl- N ,N -dimethylurea, N-vinyl-N ,N- diethylurea, etc.

The copolymers of the invention may contain in the molecule, from 1 to99%, preferably from 1 to 50% by weight of the amide and are variouslysuitable for the production of synthetic fibers, films, and shapedarticles generally, as coating compositions, and so on. In aspecifically preferred embodiment of the invention, the copolymercomprises at least 80% of acrylonitrile, and at least 1% of the amide.When the copolymer consists of acrylonitrile and an amide which iscopolymerizable with acrylonitrile, as disclosed herein, it mayadvantageously contain from 80 to 99% of acrylonitrile and from 1 to 20%of the amide. However, when the acrylonitrile and amide together totalless than 100% of the copolymer, the copolymer may be a ternarycopolymer containing, in addition to at least 80% acrylonitrile and atleast 1% of the amide, from 1 to 19% of another unsaturated monomerwhich is copolymerizable with the acrylonitrile and the amide, includingacids, such as acrylic, haloacrylic, and methacrylic acids, esters suchas methyl methacrylate, butyl methacrylate, octyl methacrylate,methoxymethyl methacrylate, chlorethyl methacrylate, and thecorresponding esters of acrylic and alpha-chloracrylic acids; vinyl andvinylidene halides such as vinyl chloride, vinyl fluoride, vinylidenechloride, vinylidene fluoride, l-fiuoro-l-chlorethylene; vinylcarboxylates such as vinyl acetate, vinyl chloracetate, vinylpropionate, and vinyl stearate; N vinyl lactams such asN-vinyl-caprolactam, N-vinyl-butyrolactam; vinyl aryl compounds such asstyrene; vinyl-substituted heterocyclic tertiary amines such as thevinylpyridines and alkyl-substituted vinylpyridines such as2-vinylpyridine and 5-ethyl-2-vinylpyridine; and other compounds such asmethyl vinyl ketone, chlortrifluoroethylene, methylfumarate, methylvinyl sulfone, methyl vinyl sulfoxide, methyl vinyl sulfide,fumaronitrile, and maleic acid or maleic anhydride.

The new copolymers may be synthesized from mixtures of the monomer byany of the known polymerization procedures including solutionpolymerization, mass or bulk polymerization, and polymerization inaqueous suspension or emulsion, in the presenceof a dispersing oremulsifying agent, the suspension or emulsion being maintained by anyagitation method, for example by tumbling in a rotating reactor, orthrough the use of any suitable rotary stirring device. A wide varietyof emulsifying agents may be used. In general, any composition havingboth hydrophilic and hydrophobic radicals may be used and the expressionemulsifying agent is intended to include commercial soaps made by thesaponification of animal and vegetable oils, such as sodium stearate,potassium laurate, ammonium oleate, and mixtures of these and othersalts as they occur in commercially available soaps. Other emulsifyingagents are the rosin soaps, the salts of sulfonated hydrocarbons,dialkyl sodium sulfosuccinates, the salts of partial esters of sulfuricacid and high molecular weight alcohols, quaternary ammonium salts suchas stearyl dimethyl benzyl ammonium chloride, non-ionic emulsifiers suchas ethylene oxide condensates of hexitan monostearates, fatty acids,mercaptans and alcohols, and hexitan monostearates.

The copolymerization reaction may be catalyzed by means of anyfree-radical-producing catalyst. Suitable catalysts include thewater-soluble peroxy compounds for example hydrogen peroxide, sodiumperoxide, sodium perborate, sodium persulfate and other alkali metalsalts of peroxy acids, or other water-soluble peroxy compounds. Azocatalysts, such as azo-2,2-diisobutyronitrile may be used advantageouslyin the copolymerization. A wide variation in concentration of catalystmay be used depending on the temperature of copolymerization, theconcentration of monomers in the reaction mass, and the molecular weightdesired for the copolymer. From 0.1 to 5% by weight may be used. Ingeneral, it i desirable to have a uniform reaction rate and therefore asubstantially uniform concentration of the catalyst is desiredthroughout the reaction. An approximation of these conditions may beobtained by separately preparing an aqueous solution and adding thesolution in increments periodically throughout the reaction.

The copolymer of the invention may also be produced by redoxpolymerization in which the copolymerization is conducted at lowtemperature in the presence of a peroxy type catalyst and a reducingagent which forms a reduction-oxidation system (redox system) with theperoxy compounds which accelerate the copolymerization.

The new copolymers can be produced, also, by a special solutionpolymerization procedure in which the solvent is saturated with acalculated mixture of the monomers, the catalyst, or a portion thereofis added, and the copolymerization is conducted just at refluxtemperature by continuously adding a mixture of the monomers inpredetermined proportion to the mass at such a rate as to keep thereflux temperature substantially constant. In this manner, the desireduniform concentration of each monomer is maintained in the reactor andthe products are substantially homogeneous with respect to bothcomposition and molecular weight. The catalyst solution may be addedcontinuously at a controlled rate to the solution to maintain thecatalyst concentration constant during the reaction.

In another embodiment, the monomers, mixed in predetermined proportion,are dissolved in the solvent, and acrylonitrile is added continuously tothe solution.

The copolymerization may be conducted in the presence of molecularweight regulators which act as chain terminators and prevent theformation of very large molecular weight increments. Such regulators areexemplified in the high molecular weight aliphatic mercaptans, such asdodecyl mercaptan and dithioglycidol, and by carbon tetrachloride.

The copolymers are soluble in a wide variety of solvents, depending onthe composition of the copolymer. Those copolymers containing at least80% of acrylonitrile and at least 1% of the amide, including ternarypolymers, are soluble in such solvents as N,Ndimethylacetamide, N,N-dimethylformamide, sulfola-ne, mixtures of nitromethane and water,mixtures of nitromethane and formamide, etc. Such copolymers areparticularly adapted to the preparation of valuable, synthetic fibers byextrusion of a solution thereof into an evaporative medium or into aliquid which is a non-solvent for the polymer. Fibers, films and otherarticles formed from the copolymers of the invention can be dyed todeep, fast shades in a dyebath containing an acid wool type dye and from1 to of sulfuric acid on the weight of the material to be dyed. The newcopolymers which contain the lesser amounts of acrylonitrile arevariously useful as coating compositions and for the production ofmolded articles. Those copolymers containing from 10 to 70% ofacrylonitrile and from to 90% of the amide are also useful for blendingwith a non-dye-receptive polymer containing at least 80% acrylonitrilein the polymer molecule to produce blends which can be dyed in anaqueous bath containing a wool type acid dye and sulfuric acid, and insuch blends may be used in a proportion of from 2 to 50% on the weightof the blend.

The evaporative medium used in dry-spinning filaments or yarns fromsolutions of the new copolymers may comprise any gaseous medium which isinert to the copolymer, such as air, nitrogen, steam, etc., or anymixture of such inert media.

The liquid non-solvent used in wet-spinning or casting the solutions ofthe new copolymers may be a mixture of water and the spinning solvent,isopropanol, glycerin, a mixture of predominantly aromatic hydrocarbonssuch as that available commercially under the trade designationSolvesso-IOO, or any appropriate liquid which is an extractive for thespinning or casting solvent and a non-solvent for the copolymer.

Further details of the practice of the invention are set forth in thefollowing examples in which the parts are by weight.

Example I To 700 parts of water there were added 24.1 parts ofN-vinyl-N-methyl-N',N'-dimethylurea and 56.5 parts of acrylonitrile. Thesolution was heated to refiux and a solution of 3.0 parts of potassiumpersulfate in 50 parts of water was added after which 80 parts ofacrylonitrile were added continuously over 26 minutes at a ratecontrolled to maintain the reflux temperature substantially constant.The mass was heated at C. for an additional 15 minutes and the copolymerwas then filtered, washed, and dried. The copolymer contained about 94%of acrylonitrile and about 6% of N-vinyl, N-methyl-N,N'- dimethylurea.

Films were formed from a dimethylacetamide solution of the copolymer byconventional casting procedures, and dyed in a dyebath prepared bydissolving 15% of sulfuric acid (96%) and 2% of the acid wool dye WoolFast Scarlet G Supra (percentages on the weight of film being dyed), inwater. The film was entered into the bath at 55 C., the bath was broughtto the boil in 10 minutes, and boiled for 60 minutes. The copolymerfilms were dyed to an acceptable red shade under these conditions.

Example II Acrylonitrile and allyl urea were copolymerized as in ExampleI, to produce a copolymer containing about 90% of acrylonitrile andabout 10% of allyl urea. Films formed from the copolymer were dyed to anacceptable red shade as in Example I.

The invention is defined by the appended claims.

I claim:

1. A copolymer containing, by weight in the polymer molecule, at leastof acrylonitrile and at least 1% of N-vinyl-N-methyl-N',N'-dimethylurea.

2. A process for preparing a copolymer which comprises heating amixture, comprising acrylonitrile andN-vinyl-N-methyl-N,N'-dimethylurea, in the presence of a polymerizationcatalyst for the mixture.

UNITED STATES PATENTS Number Name Date Caldwell Mar. 3, 1951

1. A COPOLYMER CONTAINING, BY WEIGHT IN THE POLYMER MOLECULE, AT LEAST80% OF ACRYLONITRILE AND AT LEAST 1% OFN-VINYL-N-METHYL-N'',N''-DIMETHYLUREA.